CLING and CLINGERS
The Mission
The Compliant, Low-profile, Independent, Non-protruding, Genderless and Electronic Rendezvous System (CLINGERS), investigates the integration of traditional docking mechanisms with RPO sensing to enhance safety through cooperation and real-time communication. The main goal of this project was to address limitations in the efficiency of RPO engagements by testing three modes with varying levels of cooperation and communication. Testing of CLINGERS was conducted on the International Space Station, using NASA Astrobees as a 6-DoF mobility platform to characterize the RPO modes.
CLING
Created/patented by Dr Berok Khoshnevis from USC, CLING was meant to be a genderless traditional mechanical coupling system that can be put on any type of vehicle or platform to make an automatic joint connection.
CLING + ERS
In recognition of the growing demand for on-orbit servicing applications, SERC set out to improve the safety and efficiency of spacecraft rendezvous operations. Traditionally, servicer spacecraft must perform multiple separate functions by sensing the range and bearing of a target before physically docking with it. These functions are typically handled by distinct sensor and mechanical systems. SERC initiated research with the Aerospace Corporation to investigate merging these two disparate functions into a single system. This resulted in CLINGERS, where -ERS stands for Electronic Rendezvous Sensors.
Astrobee
CLINGERS was tested inside the ISS starting in June 2023 using the Ames Research Lab's Astrobee free-flying robotic system. The use of Astrobee free-flyers has provided an invaluable experimental space to explore multi-control challenges and analyze both the limits of traditional RPO and the advantages of cooperative RPO.
Connection to Astrobee is done through their Guest Science APKs, which use its High-Level Processor (HLP) and collect data in ROS topics. The Guest Science Manager is a critical application built into the HLP that allows the APK to receive commands from the Ground Data System at Johnson Space Center. The Guest Science Library allows APKs to communicate with the Guest Science Manager Data received in the Astrobee Payload Port. This information is gathered by the CLINGERS APK, decoded, and parsed to execute Astrobee GNC.
Images courtesy of NASA.
Testing and Validation
Early ground testing at USC SERC and NASA Ames helped validate the 3 RPO modes and PnP algorithm. Testing of CLINGERS was performed in the Astrobee facility located at NASA Ames Research Center, using their Granite Lab.
ISS On-Orbit Testing
Testing for all three configurations has been performed in the 6-DoF International Space Station microgravity environment from varying initial separation distances to determine the robustness of the PnP algorithm while identifying the most efficient RPO configuration.
Publications
Please go to the Publications page for all CLINGERS publications.
Support
The CLINGERS team is grateful to the project team at CASIS for enabling this unique innovation to be tested in the ISS, and the engineers and managers at NASA Ames Research Center (ARC) for their support of CLINGERS and guidance in all of the Astrobee operations.